Techniques for Positioning Therapy Delivery Elements within a Spinal Cord or Brain

ABSTRACT

Apparatus and techniques to address problems associated with lead migration, patient movement or position, histological changes, neural plasticity or disease progression. Disclosed are techniques for implanting a lead having therapy delivery elements, such as electrodes or drug delivery ports, within a vertebral or cranial bone so as to maintain these elements in a fixed position relative to a desired treatment site. The therapy delivery elements may thereafter be adjusted in situ with a position control mechanism and/or a position controller to improve the desired treatment, such as electrical stimulation and/or drug infusion to a precise target. The therapy delivery elements may be positioned laterally in any direction relative to the targeted treatment site or toward or away from the targeted treatment site. A control system maybe provided for open- or closed-loop feedback control of the position of the therapy delivery elements as well as other aspects of the treatment therapy.

RELATED APPLICATION

This is a continuation application of U.S. application Ser. No.11/669,758 filed Jan. 31, 2007, which is a continuation application ofU.S. application Ser. No. 10/881,239 filed Jun. 30, 2004, which is acontinuation application of U.S. application Ser. No. 09/934,001 filedAug. 21, 2001, now U.S. Pat. No. 6,795,737 issued Sep. 21, 2004, whichis a division of U.S. application Ser. No. 09/303,145 filed Apr. 30,1999, now U.S. Pat. No. 6,319,241 issued Nov. 20, 2001, which is acontinuation-in-part of the earlier filed co-pending patent applicationSer. No. 09/070,136 entitled “Apparatus and Method for Expanding aStimulation Lead Body in Situ,” filed on Apr. 30, 1998, now U.S. Pat.No. 6,161,047 issued Dec. 12, 2000, for which priority is claimed. Theabove-identified applications are incorporated herein by reference intheir entireties, and priority to the above-identified applications isclaimed.

BACKGROUND OF THE INVENTION

The present invention relates to stimulation or drug delivery systems,and more particularly relates to techniques for positioning thetreatment therapy elements, such as electrodes or catheters, to providemore effective treatment therapy.

FIELD OF THE INVENTION Description of Related Art

Electrical stimulation techniques have become increasingly popular fortreatment of pain and various neurological disorders. Typically, anelectrical lead having one or more electrodes is implanted near aspecific site in the brain or spinal cord of a patient. The lead iscoupled to a signal generator which delivers electrical energy throughthe electrodes to nearby neurons and neural tissue. The electricalenergy delivered through the electrodes creates an electrical fieldcausing excitation of the nearby neurons to directly or indirectly treatthe pain or neurological disorder.

Presently, only highly skilled and experienced practitioners are able toposition a stimulation lead in such a way that the desired overlapbetween stimulation sites and target tissue is reached and desiredresults are obtained over time with minimal side effects. It requiresmuch time and effort to focus the stimulation on the desired body regionduring surgery. These leads cannot be moved by the physician withoutrequiring a second surgery.

The major practical problem with these systems is that even if theparesthesia (sensation of stimulation) location covers the pain areaperfectly during surgery, the required paresthesia pattern often changeslater due to lead migration, histological changes (such as the growth ofconnective tissue around the stimulation electrode), neural plasticityor disease progression. As a result, the electrical energy may stimulateundesired portions of the brain or spinal cord.

Maintaining the lead in a fixed position and in proximity to thetreatment site is therefore highly desirable. Presently known systemsare susceptible to lead migration. Accordingly, the lead may migratesuch that the targeted tissue is outside of the effective steerabletreatment range of the lead. Additionally, for some treatmentapplications, the lead just cannot be placed optimally to provide thedesired treatment therapy. For example, in the case of treatment oflower back pain, electrical stimulation may be provided at the middlethoracic vertebral segments, T6-T9. With currently available systems,this often fails mostly due to the great thickness of the cerebralspinal fluid (CSF) layer.

Alternatively, it is desirable to redirect paresthesia without requiringa second surgery to account for lead migration, histological changes,neural plasticity or disease progression. With present single channelapproaches, however, it is difficult to redirect paresthesia afterwards,even though limited readjustments can be made by selecting a differentcontact combination, pulse rate, pulse width or voltage. These problemsare found not only with spinal cord stimulation (S CS), but also withperipheral nerve stimulation (PNS), depth brain stimulation (DBS),cortical stimulation and also muscle or cardiac stimulation. Similarproblems and limitations are present in drug infusion systems.

Recent advances in this technology have allowed the treating physicianor the patient to steer the electrical energy delivered by theelectrodes once they have been implanted within the patient. Forexample, U.S. Pat. No. 5,713,922 entitled “Techniques for Adjusting theLocus of Excitation of Neural Tissue in the Spinal Cord or Brain,”issued on Feb. 3, 1998 to and assigned to Medtronic, Inc. discloses onesuch example of a steerable electrical energy. Other techniques aredisclosed in application Ser. No. 08/814,432 (filed Mar. 10, 1997) andSer. No. 09/024,162 (filed Feb. 17, 1998). Changing the electric fielddistribution changes the distribution of neurons recruited during astimulus output, and thus provides the treating physician or the patientthe opportunity to alter the physiological response to the stimulation.The steerability of the electric field allows the user to selectivelyactivate different groups of nerve cells without physically moving thelead or electrodes.

These systems, however, are limiting in that the steerable electricfield is limited by the location of the electrodes. If the electrodesmove outside of the desired treatment area or if the desired stimulationarea is different due to histological changes or disease migration, thedesired treatment area may not be reached even by these steerableelectrodes. Further, even if these steerable electrodes may be able tostimulate the desired neural tissue, the distance from the electrodes tothe tissue may be too large such that it would require greaterelectrical power to provide the desired therapy. It has been shown thatonly a fraction of the current from modem stimulation devices gets tothe neurons of interest. See W. A. Wesselink et al. “Analysis of CurrentDensity and Related Parameters in Spinal Cord Stimulation,” IEEETransactions on Rehabilitation Engineering, Vol. 6, pp. 200-207 (1998).This not only more rapidly depletes the energy reserve, but it also maystimulate undesired neural tissue areas thereby creating undesired sideeffects such as pain, motor affects or discomfort to the patient.

In short, there remains a need in the art to provide an electricalstimulation device that is not susceptible to lead migration and thatmay be positioned in proximity to the treatment site. In addition, thereremains a need in the art to provide an electrical stimulation devicethat may be adjusted to account for lead migration, patient movement orposition, histological changes, and disease migration.

SUMMARY OF THE INVENTION

As explained in more detail below, the present invention overcomes theabove-noted and other shortcomings of known electrical stimulation anddrug delivery techniques. The present invention provides a technique forpositioning therapy delivery elements, such as electrodes and/orcatheters, optimally closer to the desired treatment area. The presentinvention includes a therapy delivery device such as a signal generatoror a drug pump, at least one lead having at least one therapy deliveryelement coupled to the therapy delivery device and at least one positioncontrol mechanism coupled to the therapy delivery elements for adjustingthe position of the therapy delivery element relative to the excitabletissue of interest. The position may be adjusted laterally in any numberof directions relative to the lead or toward or away from the excitabletissue of interest. Any number of position control mechanisms may beincorporated to selectively adjust the position of the therapy deliveryelements. Also, a position controller such as a microprocessor may beutilized to operate the position control mechanism to position thetherapy delivery elements.

In other embodiments of the present invention, one or more of therapydelivery elements may be placed within the cranial or vertebral bone ofthe patient so as to maintain the therapy delivery elements in a fixedposition relative to the targeted neural tissue. The therapy deliveryelements may thereafter be adjusted with a position control mechanismand/or a position controller to improve the desired treatment therapy.

By using the foregoing techniques, therapy delivery elements may bepositioned to provide treatment therapy such as electrical stimulationand/or drug infusion to a precise target. Additionally, the presentinvention accounts for the problems associated with lead migration,histological changes, neural plasticity or disease progression.

Optionally, the present invention may incorporate a closed-loop systemwhich may automatically adjust (1) the positioning of the therapydelivery elements in response to a sensed condition of the body such asa response to the treatment therapy; and/or (2) the treatment therapyparameters in response to a sensed symptom or an important relatedsymptom indicative of the extent of the disorder being treated.

Examples of the more important features of this invention have beenbroadly outlined above so that the detailed description that follows maybe better understood and so that contributions which this inventionprovides to the art may be better appreciated. There are, of course,additional features of the invention which will be described herein andwhich will be included within the subject matter of the claims appendedhereto.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages and features of the invention will becomeapparent upon reading the following detailed description and referringto the accompanying drawings in which like numbers refer to like partsthroughout and in which:

FIG. 1 depicts a neurostimulation device in accordance with anembodiment of the present invention;

FIG. 2 is a cross-sectional view of spinal cord at spinal bone level T-6having an implanted lead in accordance with a preferred embodiment ofthe present invention;

FIG. 3 illustrates a position controller having metal bellows;

FIG. 4 illustrates a position controller having a piston;

FIGS. 5A-D disclose embodiments of the present invention whereelectrodes are anchored within vertebral bones of the spinal cord;

FIG. 6 discloses another embodiment of the present invention having acollar screwed into vertebral bone;

FIG. 7 discloses another embodiment of the present invention having acollar with an “O” ring to hold an electrode housing in position bypressure;

FIGS. 8 and 9 disclose other embodiments of the present invention wherea plurality of electrodes are anchored through vertebral bones of thespinal cord;

FIG. 10 discloses another embodiment of the present invention where aballoon is implemented on a dorsal side of a paddle lead;

FIG. 11 illustrates an alternative technique for adding or removingfluid to a balloon;

FIGS. 12A-B depict other embodiments wherein a plurality of balloons areimplemented to allow more selective adjustment of the electrodesrelative to the spinal cord;

FIGS. 13A-B illustrate another embodiment wherein the balloon includes arigid or semirigid dorsal component;

FIGS. 14A-B illustrate yet another embodiment wherein the balloonincludes a rigid or semi-rigid dorsal component having a hinge;

FIG. 15 depicts another embodiment of a reservoir system for adjustingfluid amounts in a lead;

FIG. 16 depicts yet another embodiment a reservoir system for adjustingfluid amounts in a lead;

FIGS. 17A-E disclose other embodiments whereby a portion of the leadbody thickness is adjusted using gliders;

FIGS. 18A-C disclose yet other embodiments whereby a portion of the leadbody thickness is adjusted using movable wires;

FIG. 19 discloses yet another embodiments whereby a portion of the leadbody thickness is adjusted using a piston and a spring;

FIG. 20 discloses yet another embodiment whereby a portion of the leadbody thickness is adjusted using a gear mechanism;

FIGS. 21A-C disclose various embodiments of the present inventionutilizing a single or dual gear mechanism;

FIGS. 22 and 23 illustrate embodiments of the present invention wheremore than one of the elements of the above figures above areimplemented;

FIG. 24 illustrates yet another embodiment of a lead having two spansextending laterally from its body;

FIG. 25 illustrates yet another embodiment of a lead having two spansthat are adjustable by use of guide struts;

FIG. 26 discloses an embodiment of a paddle lead having movable lateralspans;

FIGS. 27A-B disclose yet another embodiment of a paddle lead capable ofextending electrodes laterally;

FIG. 28 is a schematic block diagram of a sensor and an analog todigital converter circuit used in a preferred embodiment of theinvention;

FIG. 29 is a flow chart illustrating a preferred form of amicroprocessor program for utilizing the sensor to control the treatmenttherapy provided to the neural tissue;

FIG. 30 is a schematic block diagram of a microprocessor and relatedcircuitry used in a preferred embodiment of the invention;

FIGS. 31-35 are flow charts illustrating a preferred form of amicroprocessor program for generating stimulation pulses to beadministered to neural tissue;

FIGS. 36A-D illustrate other embodiments of a lead being implantedwithin a vertebral bone of a patient;

FIGS. 37A-B illustrate an embodiment of an extendable lead for implantwithin a brain; and

FIGS. 38A-C illustrate an embodiment of the present invention wherein aplurality of MCE's are implanted within the skull of a patient.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 depicts a neurostimulation therapy delivery device 14 inaccordance with an embodiment of the present invention. Therapy deliverydevice 14 made in accordance with the preferred embodiment is preferablyimplanted below the skin of a patient or, alternatively, may be anexternal device. Therapy delivery device 14 may be implanted as shown inFIG. 1, in the abdomen or any other portion of the body 10. One or moreleads 23 are positioned to stimulate a specific site in a spinal cord12. Therapy delivery device 14 may take the form of a modified signalgenerator Model 7424 manufactured by Medtronic, Inc. under the trademarkItrel II which is incorporated by reference in its entirety. Lead 23 maytake the form of any of the leads sold with the Model 7424, forstimulating a spinal cord, and is coupled to therapy delivery device 14by one or more conventional conductors 16 and 18. Lead 23 may include apaddle lead, a lead having one or more therapy delivery devices such asstimulation electrodes and/or catheters, or a combination catheter/leadcapable of providing electrical stimulation and drug delivery. Lead 23may also have recording electrodes. Exemplary embodiments of lead 23incorporating the principles of the present invention are shown in thefigures of the present application and discussed herein.

As shown in FIG. 1, the distal end of lead 23 terminates in one or moretherapy delivery elements such as stimulation electrodes generallyimplanted into or near a selected portion of the spinal cord byconventional surgical techniques. The location of the electrodes isdetermined by the type of treatment that is desired. Any number ofelectrodes may be used for various applications. Each of the electrodesare preferably individually connected to therapy delivery device 14through lead 23 and conductors 16 and 18. Lead 23 is surgicallyimplanted either by a laminotomy or by a percuntaneous needle.

Therapy delivery device or signal generator 14 may programmed to providea predetermined stimulation dosage in terms of pulse amplitude, pulsewidth, pulse frequency, or duty cycle. As preferred, a programmer 20 maybe utilized to provide stimulation parameters to therapy delivery device14 via telemetry. Programmer is coupled to an antenna 24 via conductor22.

The system may optionally include one or more sensors to provideclosed-loop feedback control of the treatment therapy and/or electrodepositioning. One or more sensors are attached to or implanted into aportion of a patient's body suitable for detecting a physical and/orchemical symptom or an important related symptom of the body. Thefeedback aspect of the present invention is discussed in further detailherein.

Although the invention will be described herein with reference to spinalcord stimulation (SCS) procedures, Cortical Surface Stimulation, and orDeep Brain Stimulation (DBS) it will be recognized that the inventionfinds utility in applications other than SCS procedures, including otherapplications such as Peripheral Nerve or Ganglia Stimulation,Intra-Spinal Stimulation, Sacral Root Stimulation, or IntraventricularCerebral Stimulation. In addition, the invention finds applicability toSCS procedures where the lead is placed in the intrathecal or subduralspace. The present invention may also be utilized to provide stimulationof various muscles of the body such as the cardiac muscle. The inventionalso finds utility to drug therapy where electrical components arereplaced with conduits and catheters for conducting drug material to thetherapy site. In this case, especially, the lead may be placed in theintrathecal or subdural space.

FIG. 2 is a cross-sectional view of spinal cord 12 at spinal bone levelT-6 having an implanted lead 23A in accordance with a preferredembodiment of the present invention. Spinal cord 12 generally includeswhite matter 27, grey matter 29, and a surrounding dural sack 30. Asshown, lead 23A is implanted in the epidural space outside of dural sack30, but may alternatively be implanted in intrathecal spinal space orsubcortically beneath dura 30. Lead 23A has a curved shape to match theshape of dura 30. The curvature may be matched to each spinal level ormay be a general shape to approximately match all levels of spinal cord.Alternatively, lead 23A may be flat such that it “grips” the vertebralbone on its dorsal edges and is less prone to migration or rotation.Lead 23A has a dorsal side 125 away from spinal cord 12 and a ventralside 120 facing spinal cord 12.

FIGS. 2-4 show the average width, height and spacing of tissuecomponents at vertebral bone level T6. The dashed lines in these figuresindicate distances of one standard deviation from the mean. See J.Holsheimer et al., “MR Assessment of the Normal Position of the SpinalCord in the Spinal Cannal,” Am. J. Neuroradiology, Vol. 15, pp. 951-959(1994).

Referring still to FIG. 2, lead 23A has two lateral electrode contacts31 and 32 at opposite ends of lead 23A and a central electrode contact33 in the central portion of lead 23A. Lateral and central electrodes31-33 may be anodes, cathodes or nonactive. Alternatively, any one ormore of lateral and central electrodes 31-33 may be recording electrodesor drug delivery ports. Lead 23A is preferably able to control thedorsal cerebral spinal fluid (CSF) width, even though it is placedoutside of dura. In accordance with the present invention, lead 23Aincludes a position control mechanism capable of adjusting the positionof one or more of the lateral or central electrodes 31-33. As shown,central electrode 33 is at a maximal distance dorsally from spinal cord12. A position control mechanism may adjust the distance between centralelectrode 33 and the spinal cord 12. In the embodiment of FIG. 2, theposition control mechanism is in the form of a cavity 34 within lead 23Awhich is able to expand and fill with fluid (controlled by a pump (notshown)) or other matter in the epidural space to reduce the separationbetween central electrode 33 and spinal cord 12. A pump (not shown) maybe powered by signal generator 14 that also provides the stimulationenergy for the electrodes at lateral and central electrodes 31-33 and asignal for controlling the position control mechanism. Alternatively,position control mechanism may be adjusted using external means andpower such as a magnetic signal, a percutaneous needle or bulb onanother component that can be pushed. Advantageously, central electrode33 may be positioned such that the targeted neural tissue is stimulatedwith optimal efficacy and minimal side effects.

As shown in FIGS. 3 and 4, the position control mechanism may take anynumber of embodiments for allowing movement of the electrodes andholding the electrodes in position. FIG. 3 illustrates a positioncontrol mechanism having metal bellows 35 and FIG. 4 illustrates aposition control mechanism having a piston 36. The bellows 35 of FIG. 3may alternatively be a threaded rod. A spring may be added to return theelectrode to a less extended position.

Further, the position control mechanism may control all or a selectivegroup of electrodes. For example, one position control mechanism maycontrol a longitudinal or transverse row of electrodes. Alternatively,each electrode to be adjusted may have its own individual positioncontrol mechanism.

The position control mechanism of the above embodiments is preferablycontrolled by a position controller which is discussed in further detailherein. The position control mechanism is preferably adjustable suchthat it does not unduly depress neural tissue or hinder blood flow.Sensing feedback may be utilized, for example by a mechanical measurewithin a lead or an ultrasound or other sensor to give information aboutthe distance. Sensing feedback may also be utilized to automaticallyadjust the positioning of the electrodes to provide optimum treatmenttherapy. Sensing feedback is discussed in further detail herein.

FIGS. 5-9 disclose another group of embodiments of the present inventionwhere electrodes are anchored to vertebral bones of the spinal cord.Alternatively, the electrodes may be implanted in the cortical bone ofthe skull. Electrodes may be positioned by drilling one or more holes atpreselected locations in the bone. Leads having one or more electrodesmay then be passed through the holes and positioned inside the vertebralcanal/skull at optimal locations or distances from the target neuraltissue. Electrodes may then be selectively adjusted in position afterthe implant. The depth of the electrodes may then be adjusted to providethe optimal stimulation therapy.

As shown in FIG. 5A, an electrode 40 at the end of a threaded housing 43is provided by drilling housing 43 into bone 42 surrounding spinal cord12. For dorsal column stimulation, bone 42 is preferably the dorsalaspect of vertebral bone. The lead 23B is coupled to electrode 40 andextends out through a top portion 41 of threaded housing 43. FIGS. 5B-Dillustrates exemplary embodiments of the top portion of housing 41 toallow for engagement of various turning devices. FIG. 5B depicts acavity 45 to provide engagement of a screwdriver-like device to turnhousing 43 to adjust position of electrode 40 relative to spinal cord12. FIG. 5C depicts a similar device but providing engagement of aslotted screwdriver-like device and showing lead 23B extending outthrough top portion 41 at point 46. FIG. 5D depicts a hexagonal cavity47 for engagement of a hexagonal wrench-like device or percutaneousneedle. Housing 43 preferably is threaded with a high pitch so that arelatively small turn provides relatively larger positioning ofelectrode 40 relative to the spinal cord 12. This minimizes the problemof lead 23B wrapping around housing 43.

FIG. 6 discloses another embodiment of the present invention having acollar 50 screwed into bone 42. An inner housing 52 similar to thehousing 43 of FIG. 5 may be used to move electrode 40 relative to collar50. This embodiment allows adjustment of electrode 40 at times after thesystem has been implanted and is less affected by growth of tissue overhousing 52 and collar 51 to limit subsequent turning of housing 52relative to collar 51. FIG. 7 discloses another embodiment where thecollar 50 has an “O” ring 54 to hold housing 53 in position by pressure.Other means to lock housing 53 in position are also possible.

As shown in FIGS. 8 and 9, a plurality of electrodes may be providedthan can be selectively or collectively adjusted relative to spinal cord12. These electrodes may also be provided in a three-dimensionalconfiguration along spinal cord 12. Further, though electrodes may bepositioned closer to spinal cord 12, they preferably do not break thedural sack 30 to avoid leakage of CSF. FIG. 9 shows a ball and socket905 or other swivel mechanism to allow turning of housing but not lead.Advantageously, placement of the lead through the vertebral bone avoidsthe problem of lead migration.

Alternatively, the lead may be implanted into the bone, as opposed toimplant all the way through the bone, as illustrated in FIGS. 36A-D. Forexample, FIG. 36A depicts a lead 5 implanted into the bony aspects ofthe vertebral body. The lumbar spine is shown with the lead insertedinto the pedicle 2 of the vertebral body 1 to stimulate nerve roots,particularly as the nerve roots 3 exit the spinal foramen 4. The lead 5is implanted by drilling a hole through the pedicle 2 (from theposterior) and into the vertebral body. The lead 5 may then be insertedinto the hole and fed to the end. Once in position, the lead 5 may beanchored at the posterior, bone entrance site using, for example, a burrcap. By keeping the lead hole medial and centered, the nerve roots canbe stimulated. The specific target nerve site may be selected by varyingthe placement of the lead relative to the vertebral bone. FIG. 36B showsan isometric drawing of pedicular placement for stimulation of the nerveroot as it exits the spinal foramen 4. Lead 5 is inserted into in theinferior portion of the vertebral pedicle 2 of the vertebral segment toenable stimulation of the dorsal root ganglion 6. By way of anotherexample, in FIG. 36C, a lead 5 placed in the superior lateral portion ofthe vertebral bone will enable stimulation of the spinal nerve 7 of thesegment superior. Advantageously, lead 5 may be placed so as to targetdesired neural tissue and avoid other tissue. In addition, lead 5 isanchored within the vertebral bone, thereby avoiding the risk of leadmigration and avoiding compression of nerve tissue common in knowntechniques.

In addition, lead 5 may be implanted in any other bone areas that areproximal to targeted neural tissue. An example of placement to targetother neural tissue is illustrated in FIG. 36C. This Figure illustratesplacement for stimulation of the ganglia (8) of the sympathetic trunk.The hole for lead 5 is angled more lateral and made deeper up to thewall of the vertebral body 1. FIG. 36D is an isometric view of the samelead placement shown in FIG. 36C. The hole in the vertebrae begins atthe posterior and is extended down the pedicle 2, into the vertebralbody 1, toward the ganglion 8, but not through the wall of the vertebralbody. This method allows stimulation of deep tissues without disruptingsoft tissue. Again the lead could be anchored in the posterior bone by aburr hole cap or other means. Lead 5 of FIGS. 36A-D may be adjustablesimilar to those of FIGS. 5-9.

The advantages of fixing a lead to a vertebral bone may also beimplemented in Cortical Brain Stimulation applications. FIG. 38Adiscloses another embodiment where one or more motor cortex electrodes(MCE) 308 are implanted into the skull of a patient for stimulationand/or recording of the cortex via contact with the dura. As shown inFIG. 38B, MCE 308 may be screwed using a burr hole ring 309 and screw310 within the skull 311 of a patient using known techniques.Advantageously, the present embodiment enables several MCEs 308 to beplaced to allow flexibility in choosing the best stimulation. A MCEtargeting grid (FIG. 38C) could be constructed of a material such as,for example, CuSO₄, so that the hole locations are visible undermagnetic resonance imaging (MRI). Placement of the MCE 308 within theskull 311 allows for more accurate placement of the MCEs 308 and avoidsthe problem of lead migration. In addition, screw 310, referring to FIG.38B, can be advanced or retracted to ensure an optimal contact betweenthe electrode 308 and dura 315 to maximize stimulation effect whileminimizing mechanical deformation of dura and cortex. Further, lessinvasive surgical procedure is required, thereby minimizing the risk ofdamage to the dura 315. Such a configuration of MCEs 308 may be used forcortex stimulation for any number of disorders, including but notlimited to, pain, epilepsy, anxiety/physiological disorders, andmovement disorders.

In addition to minimizing lead migration, the present invention alsoallows the lead to be positioned to be optimally closer to the desiredtreatment area. The embodiments discussed herein illustrate the varioustechniques that may be used to non-invasively position and re-positiontherapy delivery elements after they have been surgically implanted.Positioning of the treatment delivery elements may be laterally in anydirection or toward or away from the desired treatment site. FIG. 10discloses an embodiment of the present invention where a balloon-likestructure 60 is implemented on a dorsal side of a paddle lead 62. Theballoon may also be positioned on a lateral side of paddle lead 62.Paddle lead 62 may have one or more electrodes 64. Lead 62 may bepositioned closer to spinal cord 12 by filling of balloon 60 with afluid. In the event that it is desired that lead 62 be moved away fromspinal cord 12, fluid may be removed from 60. FIGS. 12A-B depict otherembodiments wherein a plurality of balloons are implemented to allowmore selective adjustment of the electrodes 64 relative to the spinalcord 12. These or other balloons may also be positioned on the sides ofthe lead so that the lead may be positioned from right to left. FIGS.13A-B illustrate another embodiment wherein balloon 90 includes a rigidor semi-rigid dorsal component 92. FIGS. 14A-B illustrate yet anotherembodiment wherein balloon 94 includes a rigid or semirigid dorsalcomponent 98 having a hinge 96 to allow component to form to the shapeof the dorsal aspect of the patient's vertebral canal when balloon 94 isfilled with fluid.

The amount of fluid in the balloon of FIGS. 12A-B, 13A-B and 14A-B maybe controlled by a device similar to the position mechanism of FIG. 2.These balloons may be made of an elastic or inelastic material. FIG. 11illustrates an alternative technique for adding or removing fluid toballoon 60. A septum 70 is provided just underneath the skin 72 of thepatient. A noncoring needle 74 may be utilized to deliver or removeadditional fluid to a reservoir 76 via septum 70. The delivery orremoval of fluid may then be controlled to any one of the balloons viatube 78 as needed. FIG. 15 depicts another embodiment wherein a separatereservoir and septum pair (reservoir 76A and septum 70A, and reservoir76B and septum 70B) is provided for each of two balloons. In the case ofthree balloons, three reservoir/septum pairs may be provided. FIG. 16discloses yet another embodiment wherein a single septum 80 is providedbut reservoirs 82 and 84 may transfer fluid between each other. Eachreservoir has an associated bulb or depression mechanism 86A-B that canbe accessed externally by pressing on the skin 72 of the patient. Eachdepression mechanism includes a spring 87 and ball 88 assembly. Forexample, by depressing mechanism 86B, fluid may be delivered from area79B of reservoir 84 to reservoir 82 via tube 89. Also, when bulb 86A isdepressed, fluid in area 79A is delivered from reservoir 82 to reservoir84. Also, a separate reservoir may be utilized to add or remove fluidfrom reservoirs 82 and 84. Such systems are known in the art for aninflatable urinary sphincter and an inflatable penile erector. Thesystem may allow the patient to make these adjustments as needed.

FIGS. 17A-D disclose other embodiments whereby the electrodes areadjusted using gliders GL1 and GL2. As shown in FIGS. 17A-B, gliders GL1and GL2 are constrained to move along a groove 115 transverse to ventralcomponent 120 of a lead as shown in FIG. 17C. One or more pulley systemswith wires may be utilized to move gliders GL1 and GL2 individually orcollectively. Referring back to FIGS. 17A-B, gliders GL1 and GL2 areattached to ends of rigid arms L1 and L4 respectively. The opposite endsof arms L1 and L4 are attached to joints J1 and J4 respectively whichare fixed relative to a semi-rigid or flexible dorsal component 110.Joints J1 and J4 are also connected to ends of rigid arms L2 and L3respectively. Opposite ends of arms L2 and L3 are attached to joints J2and J3 respectively which are fixed relative to ventral component 120 ofthe lead. The entire assembly may be encased within a membrane-likehousing 130 to prevent connective tissue in-growth. Ventral component120 may be positioned closer to spinal cord 12 by moving glider GL1 andGL2 relative to groove 115. As shown in FIG. 17B, ventral component 120may be closest to spinal cord when gliders GL1 and GL2 are positionedunder the joints J1 and J4. A glider may also be positioned to moveparallel to spinal cord 12 along the lead. As shown in FIG. 17D-E, anynumber of glider geometries may be utilized to adjust the position ofventral component 120.

FIGS. 18A-C discloses yet other embodiments whereby the electrodes areadjusted using movable, flexing wires. As shown in FIG. 18A, ventralcomponent 120 of a lead is positioned relative a semi-rigid dorsalcomponent 125. Wires 137 are positioned at opposite sides of theassembly. As shown in FIG. 18B, wire 137 is implemented within a sheath131 whose end is fixed to ventral component 120. The distal end of wire137 is anchored at point P1 and is also fixed relative to ventralcomponent 120 of the lead. Wire 137 may be pushed or pulled along sheath131 causing it to bend or straighten along its body 138. As wire 137 ispushed toward point P1, it bends causing the body 138 to exert pressureagainst dorsal component 125 and end P1 to exert pressure againstventral component 120. Wire 137 thus causes a portion of ventralcomponent 120 to move away from dorsal component 125 thereby causing aportion of the lead to expand and position electrodes E1 on that portionto move closer to the spinal cord 12. When wire 137 is pulled back awayfrom point P1, wire 137 reduces its pressure exerted on dorsal andventral components 120 and 125, thereby allowing a portion of the leadto reduce its thickness and electrodes E1 on that portion to move awayfrom spinal cord 12. As shown in FIG. 18C, a plurality of wireassemblies may be incorporated to adjust the position of lead 120relative to the spinal cord 12 along various points.

FIG. 19 discloses yet another embodiment whereby the electrodes areadjusted using a piston C1 and a spring S1. Piston C1 may be moved topush or pull ventral component 120 relative to semi-rigid dorsalcomponent 125. Spring 51 has a preset tension to return ventralcomponent 120 to a default position once the pressure exerted by pistonC1 is removed. As in the previously discussed embodiments, more than onepiston/spring assembly may be located laterally as well as along thelength of lead. Alternatively, bellows may be used in place of piston C1and spring S1.

FIG. 20 discloses yet another embodiment whereby the lead is adjustedusing a gear mechanism. A gear 160 may be rotated about an axis but isheld in a fixed position relative to either semi-rigid dorsal component125 or ventral component 120. Slidable elements 165 have ramped surfaceswith teeth that interact with gear 160. The upper element 165 is coupledto slide relative to semi-rigid dorsal component 125 and the lowerslidable element is coupled to slide relative to ventral component 120.As gear rotates, slidable elements 165 are moved in opposite directionsrelative to each other. With a clockwise turn of gear 160, lower element165 slides to the left and upper element slides to the right. Theelements thereby push ventral component 120 away from semi-rigid dorsalcomponent 125 and toward spinal cord 12. Two or more gears may beimplemented to minimize asymmetry in lead thickness.

As shown in FIGS. 21A-C, a gear mechanism may be incorporated into anynumber of embodiments. FIG. 21A discloses a toggle mechanism having onegear 170 attached to a component with an associated left or right wing171 a or 171 b. As gear 170 is rotated, wings 171 a-b are rotatedaccordingly. As shown in FIG. 21B, rotation of wings 171 a-bcounter-clockwise pushes up against semi-rigid dorsal component 125causing that portion of lead to increase its thickness, thereby movingthat portion of ventral component 120 toward spinal cord 12. Gear 170may be controlled by slidable toothed elements 175. As shown in FIG.21C, there may be two gears (one is shown), each connected to asingle-sided wing 171 a or 171 b to change the lateral lead thicknessindependently. Wings 171 a-b may also have transverse extensions 173 a-b(parallel to spinal cord 12) to push against dorsal component 125.

The lead may be configured in any number of ways using any combinationof the above-detailed structures. For example, FIGS. 22 and 23illustrate that two or more of the above-detailed techniques (such aswings, flexing wires and/or springs) may be combined to provide thedesired control of lead thickness.

FIG. 24 illustrates yet another embodiment of a lead according to apreferred embodiment of the present invention for use in SCS therapy.This design allows movement of electrodes toward or along spinal nerveroots within the spinal canal as they pass caudally and laterally towardtheir respective foraminae (exits from the vertebral bones). Inaccordance with known techniques, a Tuohy needle 314 is utilized andpositioned near the spinal cord. Lead body 318 is inserted through thelumen 316 of Tuohy needle 314 and positioned near the spinal cord 12. Aproximal end (not shown) of lead body 318 is ultimately to be connectedto a source device (not shown) which may be signal generator 14 of FIG.1, in the case of electrical stimulation, or a drug pump in the case ofdrug therapy. Lead 318 is provided with a distal tip 320 that may becompacted for insertion and unfolded after it has been positionedappropriately within the body. Distal tip 320 includes a central portion322 and at least one span 324 depending therefrom. Span 324 is comprisedof a flexible, insulative material, such as polyurethane or siliconerubber. The term “flexible” as used herein refers to both resilient andnon-resilient materials. Central portion 322 may have a generallysemi-circular cross-section as shown, or may be flat such as in the caseof a paddle lead (exemplified in FIG. 26). Affixed to a surface of spans324 and to central portion 322 is a series of electrodes 326. Inaccordance with the invention, lead 320 may be configured into a compactinsertion position for ease of insertion through lumen 316 of Tuohyneedle 314.

Once in position near the implant site, lead tip 320 may be deployed outof Tuohy needle 314, as shown in FIG. 24. In the embodiment of FIG. 24,spans 324 are semirigid and tend to span out at a predetermined angle.To optimally position lead spans 324 along spinal nerve roots, lead 320may be pulled back into the Tuohy needle 314. As it moves back, spans324 will tend to move laterally as well as downward, along the path of anerve root. Needle 314 may be replaced by a sheath component foradjustments after implant. In the embodiment of FIG. 25, spans 324 maybe rigid or flaccid and are coupled to a lever 330 capable of adjustingthe lateral displacement of spans 324. Lever 330 extends from spans 324to body struts 319. Struts 319 pass inside or along lead body 318 tocontrollers (not shown). As lever 330 is moved toward distal end of lead320 by pushing on struts 319, spans 324 are displaced further in alateral direction. Lever 330 may be coupled to a control mechanism suchthat spans 324 may be re-positioned at future times to provide optimaltreatment therapy. FIG. 26, discloses another embodiment of a paddlelead 419 having spans 418 which can rotate to lateral positions. FIGS.27A-B disclose yet another embodiment of a paddle lead 520 capable ofextending electrodes laterally to track along spinal nerves. Such amechanism may be similar to that of a car antenna-like device whereby arigid or semi-rigid wire may extend laterally from lead 520. An internalstylet 521 may be utilized to adjust the length of the span 522. Asshown in FIG. 27A, when stylet 521 is inserted within the lead 520 andis closest to the lead tip, the span 522 is retracted and inside lead520. As stylet 521 is pulled to the left, span 522 is directed out asshown in FIG. 27B to direct electrodes 523 laterally away from lead 520.This embodiment may be incorporated with the embodiments of FIGS. 24-26and 27A-B to allow adjustment of the extent of the lateral displacementas well as the angle of the lateral displacement.

The above embodiments illustrate various techniques for allowing therapydelivery elements to be positioned during and/or after implant toeffectively provide treatment therapy to the targeted area of the spinalcord or brain. Further, relief may be provided with a lower amplitude,and motor or other undesirable side effects may be minimized. Asexemplified in the above embodiments, any number of techniques may beutilized.

The present invention may also be utilized within the brain to provideelectrical stimulation as well as delivery of one or more drugs. Thepresent invention may be implemented within a system as disclosed inU.S. patent application Ser. No. 09/302,519 entitled “Techniques ForSelective Activation Of Neurons In The Brain, Spinal Cord Parenchyma[,and] or Peripheral Nerve,” invented by Mark Rise and Michael Baudino,now U.S. Pat. No. 6,353,762, which is incorporated herein by referencein its entirety. Treatment therapy may be provided to the brain to treatany number of diseases. Sometimes, the disease will progress to anotherpart of the brain. The present invention may thereby be used to advancethe electrodes to a different part of the brain. For example, electrodesand/or catheters may be implanted within the brain to treat tremor.Later, it may be desirable to address symptoms of akinesia orbradykinesia which were not clearly present when the treatment devicewas originally implanted. The present invention may thereby extend orshorten the leads to effect different areas of the brain tissue.Alternatively, leads may be adjusted to achieve optimal positioning.

For example FIG. 37A depicts a lead 37 composed of concentric tubes 38,preferably metal such as platinum. These tubes may be coated with apolymer except for the distal end portions 39 that serve as theelectrodes. The conductive wires 40 carrying energy to the electrodesare in the interior of the concentric tubes. Optionally, the most distalelectrode end 41 may be a small recording microelectrode to help assistin the actual placement of the lead. As shown in FIG. 37B, the lead 37may be implanted within the brain under known techniques. A pusher 142may be placed into the lead through the proximal portion to make thelead 37 stiff during the introduction phase and/or to provide amechanism to push the concentric tubes 38 out and away from the outertube or cannula 143. After implant, the outer cannula 143 may optionallybe removed.

The present invention may be operated as an open-loop controlled system.In an open-loop system, the physician or patient may at any timemanually or by the use of pumps or motorized elements adjust thepositioning of the electrodes in situ and change stimulation parameters.However, this subsequent position adjustment would be independent of anyintended changes in stimulation effect or side-effects the patient maybe experiencing, and an iterative procedure may be necessary.

Optionally, the present invention may incorporate a closed-loop controlsystem which may automatically adjust (1) the positioning of theelectrodes in response to a sensed condition of the body such as aresponse to the treatment therapy; and/or (2) the electrical stimulationparameters in response to a sensed symptom or an important relatedsymptom indicative of the extent of the disorder being treated. Under aclosed-loop feedback system to provide automatic adjustment of thepositioning of the electrodes, a sensor 130A (FIG. 28) that senses acondition of the body is preferably utilized. For example, sensor 130Amay detect patient position to discern whether the patient is lying downor is in an erect position. Typically, spinal cord stimulation becomesstrong when the patient lies down due to the spinal cord moving in adorsal direction toward the lead. In such a situation, the positioncontrol mechanism may adjust electrodes to move away from spinal cord.Alternatively, one or more recording electrodes may be utilized toprovide feedback.

More detailed description of sensor 130A, other examples of sensors andthe feedback control techniques are disclosed in U.S. Pat. No. 5,716,377entitled “Method of Treating Movement Disorders By Brain Infusion,”issued on Feb. 10, 1998 and assigned to Medtronic, Inc., which isincorporated herein by reference in its entirety.

Referring to FIG. 28, the output of sensor 130A is coupled by a cable132 comprising conductors 134 and 135 to the input of analog to digitalconverter 140A. Alternatively the output of the sensor 130A couldcommunicate through a “body bus” communication system as described inU.S. Pat. No. 5,113,859 (Funke), assigned to Medtronic which isincorporated by reference in its entirety. Alternatively, the output ofan external feedback sensor 130A would communicate with signal generator14 through a telemetry down-link. The output of the analog to digitalconverter 140A is connected to a microprocessor 200 via terminals EF2BAR and EF3 BAR. The sensor signals may then be stored in a memorydevice such as a Random Access Memory (RAM) 102 a. Such a configurationmay be one similar to that shown in U.S. Pat. No. 4,692,147 (“'147patent”) except that before converter 140A is connected to theterminals, the demodulator of the '147 patent (identified by 101) wouldbe disconnected. Microprocessor 200 may then be coupled to a positioncontroller 201.

For some types of sensors, microprocessor 200 and analog to digitalconverter 140A would not be necessary. The output from sensor 130A canbe filtered by an appropriate electronic filter in order to provide acontrol signal for position controller. An example of such a filter isfound in U.S. Pat. No. 5,259,387 “Muscle Artifact Filter, Issued toVictor de Pinto on Nov. 9, 1993, incorporated herein by reference in itsentirety.

Closed-loop control of position controller can be achieved by a modifiedform of the ITREL II signal generator. Referring to FIG. 30, the outputof the analog to digital converter 140A is connected to microprocessor200 through a peripheral bus 202 including address, data and controllines. Microprocessor 200 processes the sensor data in different waysdepending on the type of transducer in use. Microprocessor may adjustthe position of the electrodes in response to the sensor signalinformation provided by sensor 130A. The type of control provideddepends upon the type of position controller utilized and the mechanismutilized (discussed above) to position the electrodes. In the case whereposition controller relies on electrical energy to cause mechanicalmovement (e.g., pumps, motors and the like) or is purely electricalcontrol, microprocessor 200 or a second microprocessor may serve as theposition controller. In the case where position requires mechanicalcontrol, an appropriate controlling device is used. For example, in theembodiment of FIGS. 10-16 where position is controlled by filling aballoon with fluid, position controller may be incorporated within areservoir system for holding the fluid outside the lead's balloon.Torque from percutaneous instruments that engages in a mechanicalcomponent may also be used.

The present invention may also incorporate a closed-loop feedback systemto provide automatic adjustment of the electrical stimulation therapy.Such is system is disclosed in U.S. Pat. No. 5,792,186 entitled “Methodand Apparatus of Treating Neurodegenerative Disorders by ElectricalBrain Stimulation,” and assigned to Medtronic, Inc., which isincorporated herein by reference in its entirety. The system mayincorporate the same sensor 130A discussed above or one or moreadditional sensors 130 to provide feedback to provide enhanced results.Sensor 130 can be used with a closed loop feedback system in order toautomatically determine the level of electrical stimulation necessary toprovide the desired treatment. For example, to treat motion disordersthat result in abnormal movement of an arm, sensor 130 may be a motiondetector implanted in the arm. More detailed description of sensor 130,other examples of sensors and the feedback control techniques aredisclosed in U.S. Pat. No. 5,716,377 entitled “Method of TreatingMovement Disorders By Brain Infusion,” issued on Feb. 10, 1998 andassigned to Medtronic, Inc., which is incorporated herein by referencein its entirety. Other such sensors are also disclosed in U.S. Pat. Nos.5,683,422; 5,702,429; 5,713,923; 5,716,316; 5,792,186; 5,814,014; and5,824,021.

Closed-loop electrical stimulation can be achieved by a modified form ofthe ITREL II signal generator which is described in FIG. 30. The outputof the analog to digital converter 206 is connected to a microprocessor200 through a peripheral bus 202 including address, data and controllines. Microprocessor 200 processes the sensor data in different waysdepending on the type of transducer in use. When the signal on sensor130 exceeds a level programmed by the clinician and stored in a memory204, increasing amounts of stimulation will be applied through an outputdriver 224. For some types of sensors, a microprocessor and analog todigital converter will not be necessary. The output from sensor 130 canbe filtered by an appropriate electronic filter in order to provide acontrol signal for signal generator 14. An example of such a filter isfound in U.S. Pat. No. 5,259,387 “Muscle Artifact Filter, Issued toVictor de Pinto on Nov. 9, 1993, incorporated herein by reference in itsentirety.

Still referring to FIG. 30, the stimulus pulse frequency is controlledby programming a value to a programmable frequency generator 208 usingbus 202. The programmable frequency generator 208 provides an interruptsignal to microprocessor 200 through an interrupt line 210 when eachstimulus pulse is to be generated. The frequency generator 208 may beimplemented by model CDP 1878 sold by Harris Corporation. The amplitudefor each stimulus pulse is programmed to a digital to analog converter218 using bus 202. The analog output is conveyed through a conductor 220to an output driver circuit 224 to control stimulus amplitude.Microprocessor 200 also programs a pulse width control module 214 usingbus 202. The pulse width control 214 provides an enabling pulse ofduration equal to the pulse width via a conductor. Pulses with theselected characteristics are then delivered from signal generator 14 tothe lead to the target locations of spinal cord 12.

Microprocessor 200 executes an algorithm shown in FIGS. 31-5 to providestimulation with closed loop feedback control. At the time thestimulation signal generator 14 or an alternative device havingstimulation and/or infusion functions is implanted, the clinicianprograms certain key parameters into the memory of the implanted devicevia telemetry. These parameters may be updated subsequently as needed.Step 400 in FIG. 31 indicates the process of first choosing whether theneural activity at the stimulation site is to be blocked or facilitated(step 400(1)) and whether the sensor location is one for which anincrease in the neural activity at that location is equivalent to anincrease in neural activity at the stimulation target or vice versa(step 400(2)). Next the clinician must program the range of values forpulse width (step 400(3)), amplitude (step 400(4)) and frequency (step400(5)) which signal generator 14 may use to optimize the therapy. Theclinician may also choose the order in which the parameter changes aremade (step 400(6)). Alternatively, the clinician may elect to usedefault values.

The algorithm for selecting parameters is different depending on whetherthe clinician has chosen to block the neural activity at the stimulationtarget or facilitate the neural activity. FIGS. 31-35 detail the stepsof the algorithm to make parameter changes.

The algorithm uses the clinician programmed indication of whether theneurons at the particular location of the stimulating electrode are tobe facilitated or blocked in order to decide which path of the parameterselection algorithm to follow (step 420, FIG. 32). If the neuronalactivity is to be blocked, signal generator 14 first reads the feedbacksensor 130 in step 421. If the sensor values indicate the activity inthe neurons is too high (step 450), the algorithm in this embodimentfirst increases the frequency of stimulation in step 424 provided thisincrease does not exceed the preset maximum value set by the physician.Step 423 checks for this condition. If the frequency parameter is not atthe maximum, the algorithm returns to step 421 through path 421A tomonitor the feed back signal from sensor 130.

If the frequency parameter is at the maximum, the algorithm nextincreases the pulse width in step 426 (FIG. 33), again with therestriction that this parameter has not exceeded the maximum value aschecked for in step 451 through path 423A. Not having reached maximumpulse width, the algorithm returns to step 421 to monitor the feedbacksignal from sensor 130. Should the maximum pulse width have beenreached, the algorithm next increases amplitude in a like manner asshown in steps 427 and 428. In the event that all parameters reach themaximum, a notification message is set in step 429 to be sent bytelemetry to the clinician indicating that therapy delivery device 14 isunable to reduce neural activity to the desired level.

If, on the other hand, the stimulation electrode is placed in a locationwhich the clinician would like to activate to alter the symptoms of theneurological disorder, the algorithm would follow a different sequenceof events. In the preferred embodiment, the frequency parameter would befixed at a value chosen by the clinician to facilitate neuronal activityin step 430 (FIG. 34) through path 420A (FIG. 32). In steps 431 and 432the algorithm uses the values of the feedback sensor to determine ifneuronal activity is being adequately controlled. In this case,inadequate control indicates that the neuronal activity of thestimulation target is too low. Neuronal activity is increased by firstincreasing stimulation amplitude (step 434) provided it doesn't exceedthe programmed maximum value checked for in step 433. When maximumamplitude is reached, the algorithm increases pulse width to its maximumvalue in steps 435 and 436 (FIG. 35). A lack of adequate alteration ofthe symptoms of the neurological disorder, even though maximumparameters are used, is indicated to the clinician in step 437. Aftersteps 434, 436 and 437, the algorithm returns to step 431 through path431A, and the feedback sensor again is read.

It is desirable to reduce parameter values to the minimum level neededto establish the appropriate level of neuronal activity in the spinalcord. Superimposed on the algorithm just described is an additionalalgorithm to readjust all the parameter levels downward as far aspossible. In FIG. 31, steps 410 through 415 constitute the method to dothis. When parameters are changed, a timer is reset in step 415. Ifthere is no need to change any stimulus parameters before the timer hascounted out, then it may be possible due to changes in neuronal activityto reduce the parameter values and still maintain appropriate levels ofneuronal activity in the target neurons. At the end of the programmedtime interval, signal generator 14 tries reducing a parameter in step413 to determine if control is maintained. If it is, the variousparameter values will be ratcheted down until such time as the sensorvalues again indicate a need to increase them. While the algorithms inFIGS. 31-35 follow the order of parameter selection indicated, othersequences may be programmed by the clinician.

The stimulation might be applied periodically during the period ofstimulation/infusion either routinely or in response to sensor orpatient generated demand. Alternatively, in the case of simultaneousstimulation and drug therapy, stimulation could be applied continuouslywith infusion occurring periodically. Patient activation of eitherinfusion or stimulation may occur as a result of an increase in symptomsbeing experienced by the patient. Alternatively, the infusion of anagent to activate a neuronal population might be alternated withapplication of electrical stimulation of that same population.

Advantageously, the present invention may be used to selectivelyposition stimulation electrodes optimally closer to the targeted neuraltissue to more effectively deliver a desired treatment therapy. Thoseskilled in that art will recognize that the preferred embodiments may bealtered or amended without departing from the true spirit and scope ofthe invention, as defined in the accompanying claims. For example, thepresent invention may also be implemented within a drug delivery systemand/or may be implemented to provide treatment therapy to other parts ofthe body such as the brain, nerves, muscle tissue, or neural ganglia.Further, the various embodiments of the present invention may beimplemented within a percutaneous lead or a paddle lead.

1. A medical device for providing therapy to a body comprising: aplurality of leads, each lead connected to an implanted paddle lead, theimplanted paddle lead having a plurality of therapy delivery elements,the paddle lead positioned in close proximity to a target site of apatient; a plurality of threaded collars adapted to be screwed into boneof a patient, each threaded collar defining a proximal opening in a topportion of the threaded collar, a passageway through the threadedcollar, and a distal opening, wherein the proximal opening, passagewayand distal opening are adapted to allow a corresponding lead to beinserted therethrough and be disposed in close proximity to the distalopening of the threaded collar.
 2. The medical device according to claim1, wherein at least one therapy delivery element is an electrode.
 3. Themedical device according to claim 1, wherein at least one lead is acatheter and at least one therapy delivery element defines a druginfusion opening.
 4. The medical device according to claim 1, furthercomprising a means for positioning at least one therapy delivery elementcloser to a target site of a patient.
 5. The medical device according toclaim 1, wherein at least one threaded collar comprises a threaded innerhousing, wherein at least one threaded inner housing defines the distalopening, the passageway, and the proximal opening adapted to allow alead to be inserted therethrough and be disposed in close proximity tothe distal opening.
 6. The medical device according to claim 5, whereinthe top portion of at least one threaded inner housing comprises acavity adapted to be turned by a screwdriver-like device.
 7. The medicaldevice according to claim 5, wherein the top portion of at least onethreaded inner housing comprises a cavity adapted to be turned by aslotted screwdriver-like device.
 8. The medical device according toclaim 5, wherein the top portion of at least one threaded inner housingcomprises a hexagonal cavity adapted to be turned by a hexagonalwrench-like device.
 9. The medical device according to claim 5, whereinthe top portion of at least one threaded inner housing comprises ahexagonal cavity adapted to be turned by a percutaneous needle.
 10. Themedical device according to claim 5, further comprising a means forpositioning at least one therapy delivery element closer to a targetsite of a patient.
 11. The medical device according to claim 5, furthercomprising a swivel mechanism to allow turning of the threaded innerhousing but not the corresponding lead.
 12. The medical device accordingto claim 5, further comprising a ball and socket to allow turning of thethreaded inner housing but not the corresponding lead.
 13. The medicaldevice according to claim 5, wherein at least one therapy deliveryelement is an electrode.
 14. A medical device for providing therapy to abody comprising: a lead having at least one therapy delivery element ata distal end of the lead; a burr hole ring adapted to be inserted intoan opening in a skull of a patient; a threaded collar adapted to bescrewed into the burr hole ring, the threaded collar defining a proximalopening in a top portion of the threaded collar, a passageway throughthe threaded collar, and a distal opening, wherein the proximal opening,passageway and distal opening are adapted to allow the therapy deliveryelement to be inserted therethrough and be disposed in close proximityto the distal opening of the threaded collar.
 15. The medical device ofclaim 14, wherein the therapy delivery element is an electrode.
 16. Themedical device of claim 14, wherein the lead is a catheter and thetherapy delivery element defines a drug infusion opening.
 17. Themedical device of claim 14 further comprising a grid of a plurality oftherapy delivery elements.
 18. A system for providing neurostimulationtherapy to targeted tissue comprising in combination: a signalgenerator; a lead having at least one electrode at a distal end of thelead, the electrode electrically coupled to the signal generator; athreaded collar adapted to be screwed into bone of a patient, thethreaded collar defining a proximal opening in a top portion of thethreaded collar, a passageway through the threaded collar, and a distalopening, wherein the proximal opening, passageway and distal opening areadapted to allow the electrode to be inserted therethrough and bedisposed in close proximity to the distal opening of the threadedcollar.
 19. The system according to claim 18, wherein the threadedcollar comprises a threaded inner housing, wherein the threaded innerhousing defines the distal opening, the passageway, and the proximalopening adapted to allow the electrode to be inserted therethrough andbe disposed in close proximity to the distal opening.
 20. The systemaccording to claim 18, wherein the threaded collar comprises an innerhousing having an O ring to hold the inner housing in position withinthe threaded collar, wherein the inner housing defines the distalopening, the passageway, and the proximal opening adapted to allow theelectrode to be inserted therethrough and be disposed in close proximityto the distal opening.